Optical fibers used to transmit the light from the source to the spectrograph have an acceptance solid angle much less than that of the source such as tissue which spans a full 2p radians. Due to this much of the source light is not collected by the fiber. By using a non imgaging device as in compound parabolic concentrator (CPC), we have demonstrated that the light collected is 7 times more intense than that of would be collected without the CPC. This principle of using non-imaging device will have strong implication in tissue spectroscopy.